Synopsis

Getting More out of Electron Microscopy

Physics 11, s43
A new analysis technique allows researchers to extract atomic-resolution holographic images of materials using a transmission electron microscope.
J. Barthel/Jülich Research Center

With transmission electron microscopy (TEM), researchers can visualize the atomic structure within a material. Conventional TEM methods, however, often lose valuable phase information that could provide an even more detailed picture of the sample. Now researchers have demonstrated a TEM technique that can recover all available sample information at atomic resolution. The technique could offer researchers a chance to study the electrostatic potential around defects, for example.

Achieving atomic resolution with TEM is challenging, as deflections (aberrations) in the electron paths can distort the images. The sample information can be recovered by using so-called forward modeling, which involves numerically simulating TEM data. Up until now, these simulations have only been achieved for conventional TEM images, in which valuable phase information is missing.

To exploit all of the TEM information, Florian Winkler from the Jülich Research Center in Germany and colleagues devised an automated forward-modeling technique for off-axis electron holography, in which the microscope’s electron beam is split and then recombined to produce an interference pattern. The team’s technique compares holography data to simulations that account for both material properties and microscope characteristics. The simulation’s parameters are then adjusted to give the best fit to the observations. Because the fit is determined directly from the images, the protocol avoids previous problems stemming from time-varying microscope characteristics. As a demonstration, the team performed electron holography on a tungsten diselenide sample and showed that their technique could pick out a small bending of the crystal structure, as well as spatial variations in the aberrations across the image.

This research is published in Physical Review Letters.

–Michael Schirber

Michael Schirber is a Corresponding Editor for Physics based in Lyon, France.


Subject Areas

Materials ScienceCondensed Matter Physics

Related Articles

Simulations Reveal Quantum Tunneling Events in Glass
Materials Science

Simulations Reveal Quantum Tunneling Events in Glass

In a glass, the freedom of atoms to move by quantum tunneling depends on how fast the glass was initially formed. Read More »

Postponing Heat Death in Periodically Driven Systems
Condensed Matter Physics

Postponing Heat Death in Periodically Driven Systems

An exponential suppression of heating has been observed in a periodically driven optical lattice, opening up an opportunity to engineer new states of matter. Read More »

Spin Current in an Antiferromagnet is Coherent
Condensed Matter Physics

Spin Current in an Antiferromagnet is Coherent

Experiments show that a spin current moves as a coherent evanescent spin wave through an antiferromagnet layer sandwiched between two ferromagnets. Read More »

More Articles